This invention relates to a process for preparing hexafluoropropene oxide. More particularly, it relates to a process for preparing hexafluoropropene oxide by reacting hexafluoropropene with oxygen.
Hexafluoropropene oxide is useful as an intermediate of various valuable fluorine-containing compounds such as perfluorovinyl ether, of which a low molecular weight polymer is used as a heat resistance fluid.
For preparation of hexafluoropropene oxide, there is known a process comprising reacting hexafluoropropene with oxygen in a liquid medium or in a gaseous phase. The reaction in a gaseous phase is particularly favorable for industrial production of hexafluoropropene oxide, because of its operational advantage and other ones.
In the gaseous phase reaction, the reaction preferably proceeds in the presence of a catalyst. As such catalyst, there are known several ones including silica gel treated with hydrogen chloride and then with oxygen and hexafluoropropene and/or hexafluoropropene oxide (U.S. Pat. No. 3,775,439), a catalyst mainly composed of copper supported on silica alumina (Japanese Patent Publication (unexamined) No. 53804/1977), a zeolite catalyst ion-exchanged with a transition metal (Japanese Patent Publication (unexamined) No. 53805/1977) and a catalyst mainly composed of copper supported on silica gel (Japanese Patent Publication (unexamined) No. 53806/1977). The preparation of these catalysts is, however, very troublesome.